Assessing the effects of land-use and climate change on the plant distribution under limited migration capacity

Background/Question/Methods: The objective of the present study was to compare the roles of dynamic land use and land cover (LULC) change, climate change, and migration capacity on the projected distribution patterns of five warm-adapted evergreen broadleaved plants, Pittosporum tobira, Raphiolepis indica var. umbellata, Neolitsea sericea, Ilex integra, and Eurya emarginata in the Republic of Korea. For this, we first projected current and future (2070) climatically suitable habitats for each species using an ensemble species distribution model (SDM), traditional SDM projections. Then, a GIS-based cellular automata model, MigClim, was applied to project future distributions under four dispersal scenarios (no dispersal, realistic dispersal, realistic dispersal with long distance dispersal event, full dispersal), two LULC change scenarios (Shared Socioeconomic Pathway (SSP) 1 and 3), and two climate change scenarios (Representative Concentration Pathway (RCP) 4.5 and 8.5). We simulated the LULC changes with Scenario Generator of InVEST and used the climate change projections simulated with HadGEM-ES global circulation models (GCMs).

Results/Conclusions: The traditional SDM projections showed the expansions of all five species in 2070, but, given the dispersal limitations and LULC changes, we found significant decreases in future distributions, especially under no dispersal + SSP1 + RCP 4.5, or in the level of expansion. As comparing the traditional projections, the level of expansion decreased approximately 50 % under climate change, the LULC change and dispersal limitations. In addition, the maximum increases in future distributions for all five species were projected under full dispersal + SSP1 + RCP 8.5. As comparing the effects of LULC change, climate change and dispersal limitation on the future distributions, the LULC change was dominant. Therefore, our results suggested that the LULC change was the most effective factor in controlling species distributions.